The conventional fine structures having microprojections on their surfaces and methods of producing such structures are reviewed below.
In a first instance of the conventional fine structures having microprojections on the surface and their production methods, an inorganic material such as silicon, a metal such as nickel or an organic material such as polystyrene or resist is directly worked by a fine working technique such as lithography or anisotropic etching using a mask, and the obtained work is directly used as a structural member of a metal mold or microdevice. (See Patent Document 1).
In a second instance of the conventional fine structures having microprojections on the surface and their production methods, a resin such as polystyrene is pressure molded by using as its mold a fine structure obtained in the same way as in the first instance described above, and the molded product is detached from the mold and utilized as a fine structure. (See Patent Document 2).
In a third instance of the conventional fine structures having microprojections on the surface and their production methods, a fine structure obtained in the same way as in the first instance described above is used as a casting mold, the inside thereof is filled up by electroplating, and the formed plating film is detached from the mold and utilized as a fine structure. (See Patent Document 3).
With reference to the third instance, it is disclosed that in case a high hardness is required for the stamper surface, the stamper is made by electroless plating with NiP alone and the obtained stamper is heat treated at around 400° C. for 4 hours, whereby it is possible to obtain a HV hardness of 1,000 or higher. (See Patent Document 4).
Patent Document 1: JP-A-2002-307398
Patent Document 2: U.S. Pat. No. 5,772,905
Patent Document 3: Japanese Patent No. 2633088
Patent Document 4: JP-A-2003-22585 (paragraph [0040])